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Chapter 2 Unix Kernel & TCP/IP Protocols Part 1: Unix Kernel Review. Network Protocols are implemented in either hardware or software, examples. Basic structure for the implementation of different layer protocols in a computer system
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Chapter 2 Unix Kernel & TCP/IP ProtocolsPart 1: Unix Kernel Review • Network Protocols are implemented in either hardware or software, examples. • Basic structure for the implementation of different layer protocols in a computer system • Network software development and computer language.
From a point of view networking Kernel Process & Program Multitasking Shells Files Talking to the kernel Systems calls C library File management Process management Error handling Review Concepts in the Unix
Error handling What’s the difference between signal functions and the IPC for processes communications? perror
Process Relationships • A special process - init • Daemons are processes that live for a long time • Put a process in a background % server port & % client dest-ip [-options] /* see processes states */ % ps -axj
Interprocess Communication (IPC) • Network programming with multiple processes • IPC between two processes on a single system, such as using pipe. Based on sharing memory • IPC between two distributed processes on different machines - BSD Sockets Based on messages exchange through the networks
The Structure of TCP/IP software in an Operating System • TCP/IP software usually resides in the operating system, where it can be shared by all application programs on the machine. • What’s the general structure of TCP/IP software? • How the software fits into the operating System?
What are required to implement TCP/IP protocols in the kernel? • Multiple processes • Process Priority • IPC • Processes mutual exclusion & Synchronization • Today, for multimedia communications, real-time OS kernel is needed
Structure of TCP/IP software • Device drivers, input and output • Network input and interrupts • Passing packets to high level protocols • Passing datagrams from IP to transport protocols • Delivery to application programs
Summary of Output Process Structure • It shows the path of data between an application program and network hardware. • Output from the device queues is started at interrupt time. • IP is a central part of the design - the software for input and output both share a single IP process.
Application(User processes) Overview of data output flow TCP/UDP/IP in the kernel of OS Physical network
Summary of Input Process Structure • It shows that the path of data between the network hardware and an application program. • Input to the device queues occurs asynchronously with processing. • IP is a central part of the design - the software for input and output share a single process.